Browse Topic: Braking systems
The traditional braking system has been unable to meet the redundant safety requirements of the intelligent vehicle for the braking system. At the same time, under the change of electrification and intelligence, the braking system needs to have the functions of braking boost, braking energy recovery, braking redundancy and so on. Therefore, it is necessary to study the redundant braking boost control of the integrated electro-hydraulic braking system. Based on the brake boost failure problem of the integrated electro-hydraulic brake system, this paper proposes a redundant brake boost control strategy based on the Integrated Brake Control system plus the Redundant Brake Unit configuration, which mainly includes fault diagnosis of Integrated Brake Control brake boost failure, recognition of driver braking intention based on pedal force, pressure control strategy of Integrated Brake Control brake boost and pressure control strategy of Redundant Brake Unit brake boost. The designed control
This SAE standard specifies a method for testing and measuring a normalized elastic constant of brake pad assemblies using ultrasound. This document applies to disc brake pad assemblies and its coupons or segments used in road vehicles
Heavy-duty vehicles, particularly those towing higher weights, require a continuous/secondary braking system. While conventional vehicles employ Retarder or Engine brake systems, electric vehicles utilize recuperation for continuous braking. In a state where HV Battery is at 100% of SOC, recuperated energy from vehicle operation is passed on to HPR and it converts electrical energy into waste heat energy. This study focuses on identification of routes which are critical for High Power Brake Resistors (HPRs), by analyzing the elevation data of existing charging stations, the route’s slope distribution, and the vehicle’s battery SOC. This research ultimately suggests a method to identify HPR critical vehicle operational routes which can be useful for energy efficient route planning algorithms, leading to significant cost savings for customers and contributing to environmental sustainability
Brake disc temperature is a critical factor influencing the performance and wear characteristics of braking systems in automobiles. Hence it is very important to optimize the correlation of brake disc temperature prediction with test. In this study critical parameters of Brake Disc temperature evaluation are identified, and algorithm is used to optimize the critical parameters to achieve the correlation of prediction with experiment data. Through a series of controlled experiments and simulations, disc temperatures are monitored under different braking conditions and simultaneously input parameters for prediction are optimized to achieve the correlation. Statistical methods were applied to evaluate the observed correlations and to model the predictive behavior of brake disc temperatures. Finally, A front-loading tool is developed to optimize the brake disc keeping target thermal capacity via algorithm. The findings of this study are expected to contribute to the enhancement of brake
The SAE J2923 procedure is a recommended practice that applies to on-road vehicles with a GVWR below 4540 kg equipped with disc brakes
Komatsu introduced its first battery-electric load-haul-dump (LHD) machine, the WX04B, at the MINExpo tradeshow in September. The WX04B is designed specifically for narrow vein mines in underground hard rock mining operations. Komatsu is pairing the electric LHD with its new OEM-agnostic 150-kW battery charger that was also revealed in Las Vegas. The 4-tonne WX04B LHD features what Komatsu claims is best-in-class energy density, offering up to four hours of runtime on a single charge. The Li-ion NMC (nickel-manganese-cobalt) battery from Proterra has a capacity of 165 kWh and nominal voltage of 660 V. Fewer charge cycles are needed compared to competitors, the company claims, which helps to maximize operational efficiency and minimize downtime. Proterra and Komatsu began their collaboration on the LHD's H Series battery system in 2021, long before Komatsu's acquisition of American Battery Solutions (ABS) in December 2023
This SAE Recommended Practice provides instructions and test procedures for measuring air consumption of air braked vehicles equipped with Antilock Brake Systems (ABS) used on highways
This recommended practice shall apply to all on-highway trucks and truck-tractors equipped with air brake systems and having a GVW rating of 26 000 lb or more
ABSTRACT In this paper, a conceptually new research direction of the tire slippage analysis is provided as a new technological paradigm for agile tire slippage control. Specifically, the friction coefficient-slippage dynamics is analyzed and its characteristic parameters are introduced. Next, the nonlinear relation between the wheel torque and the tire instantaneous rolling radius incorporating the longitudinal elasticity factor is analyzed. The relation is shown to be related to the tire slippage. Further, its importance is clarified by deriving its dynamics and specifically, the instruction is given how it can be utilized to control slippage. Finally, the indices are introduced to assess the mobility and agility of the wheel in order to achieve optimal response to severe terrain conditions. The indices comprise of the introduced friction coefficient-slippage characteristic parameters. Citation: M. Ghasemi, V. Vantsevich, D. Gorsich, J. Goryca, A. Singh, L. Moradi, “Physics Based
ABSTRACT Teleoperated ground vehicles are an integral part of the U.S. Army and Marine Corps long range vision and a key transition technology for fully autonomous vehicles. However, the combination of marginally-stable vehicle dynamics and limited perception are a key challenge facing teleoperation of such platforms at higher speeds. New technologies for enhancing operator perception and automatically detecting and mitigating rollover risk are needed to realize sufficient safety and performance in these applications. This paper presents three rollover mitigation concepts for high speed teleoperation of heavy tactical vehicles, including model-predictive warning, negative obstacle avoidance, and reactive brake controls. A modeling and simulation approach was used to evaluate these concepts within the Autonomous Navigation Virtual Environment Laboratory (ANVEL). Vehicle models for both the M1078 cargo truck and RG-31 MRAP were used throughout concept evaluation over terrain ranging from
ABSTRACT When building simulation models of military vehicles for mobility analysis over deformable terrain, the powertrain details are often ignored. This is of interest for electric and hybrid-electric vehicles where the maximum torque is produced at low speeds. It is easy to end up with the drive wheels spinning and reducing traction and eventually the vehicle digging itself down in the soil. This paper reveals improvements to mobility results using Traction Control Systems for both wheeled and tracked vehicles. Simulations are performed on hard ground and two types of deformable soil, Lethe sand and snow. For each soft soil, simulations have been performed with a simple terramechanics model (ST) based on Bekker-Wong models and complex terramechanics (CT) using the EDEM discrete element soil model which Pratt & Miller Engineering (PME) has been instrumental in developing. To model the traction control system a PD controller is used that tries to limit the slip velocity at low speed
ABSTRACT Future wheeled and tracked military vehicles will be equipped with multiple active chassis control systems, as systems currently in widespread use on passenger and commercial vehicles such as brake-based electronic stability control are implemented on military vehicles. It is essential that these systems work in an integrated fashion to avoid negative interactions between systems. The approach currently used to achieve integrated control in the passenger and commercial vehicle segments requires extensive tuning and development of the individual systems through cooperative efforts of the vehicle and active chassis system manufacturers, an approach that would generally not be feasible in the military vehicle segment. This paper presents a simple approach for achieving integrated control of multiple active chassis systems that is tailored to the unique commercial and developmental challenges faced by military vehicles
ABSTRACT This paper provides detail of the system architecture and systems engineering process utilized by AM General to develop a new stability control system that satisfies all military and federal safety requirements for wheeled, light tactical vehicles
ABSTRACT A new integrated testing system for the validation of stochastic vehicle-snow interaction models is presented in this paper. The testing system consists of an instrumented test vehicle, vehicle-mounted laser profilometer and a snow micropenetrometer. The test vehicle is equipped on each tire with a set of 6-axis wheel transducers, and a GPS-based data logger tracks vehicle motion. Data is also simultaneously acquired from the sensors from the test vehicle’s Electronic Stability Program. The test vehicle provides measurements that include three forces and moments at each wheel center, vehicle body slip angle, speed, acceleration, yaw rate, roll, and pitch. The profilometer has a 3-D scanning laser and an Inertial Measurement Unit to compensate for vehicle motion. Depth of snow cover, profile of snow surface and wheel sinkage can be obtained from the profilometer. The snow micropenetrometer measures the strength of the snow cover before and after vehicle traversal. Preliminary
ABSTRACT The Army has identified an operational need for a Robotic Convoy capability for its tactical vehicle fleets. The Department of Defense (DoD), with a fleet of over several hundred thousand tactical vehicles, must identify an approach with supporting technology and supply base to procure and support a Robotic Convoy solution at the lowest possible cost. While cost is a key driver, the selected system approach must be proven and robust to ensure the safety of our soldiers and the supply chain. An effective approach is to integrate and adapt the advanced automotive technologies, components and suppliers currently delivering advanced safety technologies into the automotive market. These advanced automotive technologies merged with DoD robotics enhancements in tactical behaviors, autonomous driving, command & control and unmanned systems collaboration will advance the operational utility of robotic convoy application in manned and unmanned modes. Figure 1 Military Application The
ABSTRACT This paper discusses the semi-active suspension system developed by A.M. General to provide mobility and maneuverability for tactical, wheeled vehicles
Many performance sport passenger vehicles use drilled or grooved cast iron brake rotors for a better braking performance or a cosmetic reason. Such brake rotors would unfortunately cause more brake dust emission, appearing with dirty wheel rims. To better understand the effects of such brake rotors on particle emission, a pin-on-disc tribometer with two particle emission measurement devices was used to monitor and collect the emitted airborne particles. The first device was an aerodynamic particle sizer, which is capable of measuring particles ranging from 0.5 to 20 μm. The second device was a condensation particle counter, which measures and collects particles from 4 nm to 3 μm. The testing samples were scaled-down brake discs (100 mm in diameter) against low-metallic brake pads. Two machined surface conditions (plain and grooved) with uncoated or ceramic-coated friction surfaces were selected for the investigation. The results showed that the grooved friction surface led to a higher
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